The famed cosmologist has reinvented the way we understand the universe, from black holes to the dawn of time.

He also has some idea of what was going on before time even began.

In a conversation with astrophysicist Neil deGrasse Tyson, Hawking explained that there was basically nothing going on before the Big Bang, which started our universe.

“Nothing was around before the big, big bang,” Hawking said. “According to Einstein’s General Theory of Relativity, space and time together form a space-time continuum or manifold which is not flat but curved by the matter and energy in it.”

Hawking went on to basically explain that before the Big Bang, time didn’t exist.